Constructor to create an instance of this class. The constructor sets up the
singleton object and reads the config from
'data/config/' . CON_ENVIRONMENT . '/config.http_check.php' It also reads
existing local config from
'data/config/' . CON_ENVIRONMENT . '/config.http_check.local.php'

Constructor to create an instance of this class. The constructor sets up the
singleton object and reads the config from 'data/config/' . CON_ENVIRONMENT .
'/config.http_check.php' It also reads existing local config from 'data/config/'
. CON_ENVIRONMENT . '/config.http_check.local.php'